Graffiti artwork on display in South Korea has been damaged by a couple who thought brushes and paint laid in front of the piece were for visitors' use, BBC News reports.
"They thought they were allowed to do that as participatory art and made a mistake," the head of the exhibition in Seoul told Reuters news agency.
After staff spotted fresh brushstrokes CCTV footage identified the accidental vandals, a man and woman in their 20s.
The untitled piece is estimated to be worth about $500,000 (£360,000).
It was painted by US graffiti artist JonOne in front of an audience in Seoul in 2016.
It has since been displayed at various venues, along with the paint and brushes used in the live performanc...